Clasps answering the general definition given hereinbefore are already known. European Patent No. 0 125 930 discloses, for example, such a clasp for ensuring the electrical connection of two conductors housed in the strands of a wristband for forming loop antenna around the user's wrist when the electronic instrument is being worn.
U.S. Pat. Nos. 5,152,693 and 5,179,733 disclose another solution that, like the aforementioned solution, has the possibility of adjusting the position of one of the clasp elements on one of the wristband strands. Yet another similar solution is given in U.S. Pat. No. 5,303,421.
Finally, another solution is known wherein the clasp is of the type with a buckle with a tongue (cf. particularly WO 86/03645), of the type with male and female parts that plug into one another (cf. again WO 86/03645), or of the type with an unfolding buckle (cf. particularly EP 0867 968).
The buckle with a tongue solution is not suitable in practice because of the poor quality of the electric contact, and the plug-in type solution is complex from a mechanical point of view. As for the other aforementioned solutions, it should be noted that these solutions expose parts of the antenna elements on the internal or external face of the wristband. This type of solution thus has a drawback insofar as the exposed parts of the antenna elements can quickly become oxidized and thus cause the quality of the electric contact to deteriorate. This oxidization is accelerated, in particular, by the presence of sweat when the wristband is worn on the wrist. From an aesthetic point of view, this type of solution is also not very desirable.
Another drawback of these solutions lies in the relatively large thickness of the wristband around the fastening device, the two strands of the wristband being superposed there.